feat(args): add --write flag for only enabling the write mode

systeroid/src/app.rs

@@ -118,7 +118,12 @@ impl<'a> App<'a> {
     }
 
     /// Updates the parameter if it has the format `name=value`, displays it otherwise.
-    pub fn process_parameter(&mut self, mut parameter: String, display_value: bool) -> Result<()> {
+    pub fn process_parameter(
+        &mut self,
+        mut parameter: String,
+        display_value: bool,
+        write_mode: bool,
+    ) -> Result<()> {
         let new_value = if parameter.contains('=') {
             let fields = parameter
                 .split('=')
@@ -142,6 +147,12 @@ impl<'a> App<'a> {
                     param.update_value(&new_value, &config, &mut self.stdout)?;
                 }
             }
+        } else if write_mode {
+            eprintln!(
+                "{}: {:?} must be in the format: name=value",
+                env!("CARGO_PKG_NAME"),
+                parameter
+            );
         } else if display_value {
             self.sysctl
                 .get_parameters(&parameter)
@@ -166,7 +177,7 @@ impl<'a> App<'a> {
         }
         let contents = reader::read_to_string(path)?;
         for parameter in contents.lines() {
-            self.process_parameter(parameter.to_string(), false)?;
+            self.process_parameter(parameter.to_string(), false, false)?;
         }
         Ok(())
     }

systeroid/src/args.rs

@@ -22,6 +22,8 @@ pub struct Args {
     pub verbose: bool,
     /// Whether if the quiet mode is enabled.
     pub quiet: bool,
+    /// Whether if only the write mode is enabled.
+    pub write: bool,
     /// Path of the Linux kernel documentation.
     pub kernel_docs: Option<PathBuf>,
     /// Display type of the variables.
@@ -67,6 +69,7 @@ impl Args {
             "<expr>",
         );
         opts.optflag("q", "quiet", "do not print variable after the value is set");
+        opts.optflag("w", "write", "only enable writing a value to variable");
         opts.optflag("d", "", "alias of -h");
         opts.optflag(
             "E",
@@ -141,6 +144,7 @@ impl Args {
             Some(Args {
                 verbose: matches.opt_present("v"),
                 quiet: matches.opt_present("q"),
+                write: matches.opt_present("w"),
                 kernel_docs: matches.opt_str("d").map(PathBuf::from),
                 display_type,
                 display_deprecated: matches.opt_present("D"),

systeroid/src/lib.rs

@@ -41,7 +41,7 @@ pub fn run(args: Args) -> Result<()> {
         }
     } else {
         for param in args.values {
-            app.process_parameter(param, true)?;
+            app.process_parameter(param, true, args.write)?;
         }
     }